Re: Advice on oscilloscopes

bluesky · « **on:** 13 Sep 2005, 11:40 am »

Hi Everyone

I am pondering getting an oscilloscope, and this is from someone who knows bugger all about them! However the couple of times I have seen them action I found it amazing how a person with expertise could find faults, see the clipping etc etc.

At some stage I would like to get one but baulk at the very high cost of new ones.

I would like some sage advice on what to get and, if possible, a good spiurce for second hand oscilloscopes.

Thanks in advance,

Bluesky

ctviggen · « **Reply #1 on:** 13 Sep 2005, 12:44 pm »

What are you going to do with it? I'd recommend figuring out what speed (aka sampling rate) you need. The higher the sampling rate, the more expensive. How many channels do you need? What type of probe? Do you want digital or analog? (Digital is nice, because you can set a trigger point and it will record what happens; with analog, the trigger has to constantly be there.) If you're looking for something like rise time for a digital IC, then analog would be fine (though again digital would allow you to trigger once and maintain that, while analog is going to have to constantly trigger).

Ebay's a good place:

http://cgi.ebay.com/Philips-PM3365A-100MHz-2ch-Oscilloscope-w-Probes-NICE_W0QQitemZ7545075756QQcategoryZ104247QQrdZ1QQcmdZViewItem

(as an example)

bluesky · « **Reply #2 on:** 14 Sep 2005, 02:27 am »

Hi Bob

Thanks for your advice! I would use an oscilloscope mainly for trouble shooting and repair work on amps and preamps, both solid state and tubed. However I still have much to learn and it appeared to me that being able to use an oscilloscope would make trouble shooting so much easier than the trial and error I use at the moment.

Cheers

Bluesky

Rom · « **Reply #3 on:** 14 Sep 2005, 06:28 am »

Hi Bluesky,

With your requirement, I would recomment analog osciloscope,
I have used Fluke scopemeter and find the response time and resolution is not on par with the analog, one of the nice digital scope meter that I found much better than the fluke is the tektronix, sorry can't remember the models.

I still prefer analog scope than any of the 3 digital handheld that I've used even the desk top one.

The tektronix if you can afford them are one really nice to have and easy to use but the HP are not that bad and the Hitachi's as well are up there as well.

Good luck with your hunt.

Cheers
rom

bluesky · « **Reply #4 on:** 14 Sep 2005, 10:25 am »

Hi Rom

I find it interesting that you recommend analogue when just about everthing is digital now, your advice on brands is much appreciated.

I will keep a close eye on Ebay and see if I can grab a bargain at some stage.

Cheers

Bluesky

bluesky · « **Reply #5 on:** 17 Sep 2005, 08:57 pm »

Hi Guys

A couple of questions if I may. There are a couple of kits available through Jaycar etc that may be useful but having had no experience I would appreciate any advice on this.

There is an interesting kit that uses the sound card of your PC to mimic an oscilloscope with software downloaded from the interenet and also a signal generator kit. Does anyone have an opinion on the usefulness of these?

I am trying to read up on how to use an oscilloscope but finding the text books pretty heavy going and something that would beat the hell out of sleeping tablets at bedtime!

Thanks in advance,

Bluesky

amplifierguru · « **Reply #6 on:** 24 Jan 2006, 12:30 am »

Hi bluesky,

I have an older (1990) printer port connected 2 channel 100KHz sampling 14bit oscilloscope with DOS based software. It has all on screen pull down menus, the box has BNC's for two CRO probes. It is excellent for educational and illustrative pics as you can just save screens, place cursors, display voltage points, etc... It was designed in NZ for educational instutions by Strobes who have now changed name and make upmarket PC based CROs.

I use an analog 20MHz with scale magnification by Protech from Altronics, because I need analogue for amplifier stabilizing, just not as clear with digital. There are also little single channel 10MHz cheapies from Dick Smith for about $150.

Cheers,
Greg

bluesky · « **Reply #7 on:** 24 Jan 2006, 01:22 am »

Hi

Well, I bit the bullet and went into hock to get the 20MHz scope on special at Altronics. It was "only" $399 but this was nearly half the usual price.

I just need to learn how to use it now.

By the way I can't speak too highly of Altronics' service, they always go way beyond expectations, and, when there has been a problem, it was (cheerfully) corrected immediately and at no cost to me (the same could not be said of the other major suppliers in similar circumstances). I strongly recommend Altronics for all your electronics suppies, I just wish they carried things like Black Gates etc.

Cheers

Bluesky

amplifierguru · « **Reply #8 on:** 24 Jan 2006, 02:08 am »

Hi Bluesky,

Same as I have. Now you need a signal generator sine/sq wave with less than 1uS rise/fall time.

Don't need blackgates, more hype than substance.

Cheers,
greg

bluesky · « **Reply #9 on:** 24 Jan 2006, 04:10 am »

Hi Greg

That's good news that I appear to have bought the right model!

I have developed a bit of a friendship with Chung from vt4c in Hong Kong and he can supply me a signal generator for about $55USD but I don't know if it is suitable. Now I know what to look for I will ask him if it meets the requirements that you outlined.

Thanks heaps for your advice, it has been invaluable!

Ian

amplifierguru · « **Reply #10 on:** 24 Jan 2006, 04:36 am »

No worries bluesky,

Sounds like a fair price. Just ask him for a spec on it and post it. I built my own which was cheaper but less functional than a bought one.

Happy to help.

Cheers,
greg

bluesky · « **Reply #11 on:** 24 Jan 2006, 08:45 am »

Hi Greg

Where are you in Australia? Not Brisbane, by any chance?

Bluesky

amplifierguru · « **Reply #12 on:** 26 Jan 2006, 03:15 am »

Hi bluesky,

Bribie Island. I like to have a body surf before designing/building amps all day.

cheers,
greg

bluesky · « **Reply #13 on:** 26 Jan 2006, 07:56 am »

Hi Greg

Now that is a good lifestyle, surfing and playing with audio electronics all day.

I checked your website, some very interesting stuff indeed! Once I complete my various amp projects it would be good to compare them with your design.

Cheers

Bluesky